Lawl. 

Uh...I hate to break it to you, but every Final Fantasy game is EXTREMLY Linear.  This isn't Dragon Quest or Pokemon where they give you a vague list of objectives, a backpack and say 'go explore the world at your leisure and have fun!'  Final Fantasy is the epitome of 'Here, let me tell you where to go, what to do....forget that, let me draw you a map, close off all the adjacent roads, put up signs and NPCs along the way pointing you to where you need to go and make CUTSCENES leading you in the right way, just so you don't get sidetracked.'

I think a better question, OP, is "why are people loving FFXIII?" and the answer is, because it's great, I'd assume, and so do many players. Every FF, from VII on out(as is made perfectly clear in this thread) is "love it or hate it." If you've loved them all so far, good bet is that you'll love this one.

Every FF except XII has been very linear, and everybody hated XII(but me) so WTF, lol? That's the big complaint? The game isn't even going good at 20 hours, and all the minimaps are linear on all the FF's except for the random chest cubbies and crannies, for the first 20, jeez.

More people love it, than hate it, and that means it's already doing better than every FF since VII.

I think you have a very warped view of Final Fantasy.  Or, more likely, you're mixing the American Western extremist view with the Japanese fanbase.  Which they loved FFVIII and X.  It can be argued that the reason FFXIII might be showing signs of being more of a conglomeration of all the past PlayStation Final Fantasy games (from FFVII-XII) is because the Japanese fanbase has been a strong supporter of all the major Playstation Final Fantasy games across the board, except FFIX.

My ex housemates in Japan have the game and told me what they thought of it.
One of them loved it and had next to no previous experience of the series beyond number 7. One of them who is a bigtime series fan said she hated it for basically the same reasons a lot of you have mentioned, but mainly because the world feels very empty with not much to do in comparison to older versions. You don't feel the sense to explore etc.. And the last one who has played all of the games for all of the formats says he loves it and has not stopped playing it since he got it. He says it is not as good as some of the others but is a lot better then a lot of them too.

So to me it seems 2 out of 3 liking it is pretty good going. Sure people will have bits they dislike or wish could be better. Every game has that. But overall it should be fun to fans of the series, maybe not the best in the series but by going on what people are saying it is far from the worst. And that = instant buy from me.

FF8 was easily my favourite... But it had lots of towns, the best towns in the whole series.

Oh cool, when did you buy your PS3? No wait...your "friend has one that you can play"?

You do remember FFIII is on 360... right?

Interchangeable. His profile and system tags lead me to believe he only owns a Wii, which was my point.

OP says that FFXIII is akin to FFX; Bioware says JRPGs suffer from a lack of evolution. I think I see a correlation here.